In the oil production industry, there are numerous instances where an inexpensive and reliable source of heat is required in order to carry out profitable production. It is customary for the various sizes and configurations of vessels used in production of oil to be heated in the most simple and economical manner possible, because they must have the capability of efficiently operating over a projected period of time without any attention. The heat transfer apparatus often includes a direct fired tubular type conduit which is enclosed within a vessel in such a manner that the interior of the tube can be directly fired by the combustion products provided by a gas burner. There is usually ample raw gaseous hydrocarbons available in the oil patch for use as fuel.
It is therefore desirable to have made available a rugged, efficient burner device which can directly fire a heat exchanger, and which can be easily controlled so that the temperature of the vessel is maintained at any reasonable predetermined value. It is necessary that the burner have a reliable pilot light associated therewith so that ignition always occurs during initiation of the heating cycle. It is further desirable that the burner be efficient in operation, low in cost, rugged in design, and reliable in operation.